I have to disagree, as the lamb did not take away sin till the sacrifice, that is made clear in the instructions and why the ceremonies were laid out so detailed.

I don't think our salvation depends on this point of when the sins were put on Christ, so lets leave it for now till we have time to study it and maybe some more from others who may have something specific and see if it is made clearer.

The sacrifice of Christ, so far as this world is concerned, dates from the foundation of the world. While Christ was going about doing good in Judea and Galilee, He was in the bosom of the Father making reconciliation for the sins of the world.

The scene on Calvary was the manifestation of what has taken place as long as sin has existed, and will take place until every man is saved who is willing to be saved: Christ bearing the sins of the world. He bears them now. One act of death and resurrection was sufficient for all time, for it is eternal life that we are considering; therefore, it is not necessary for the sacrifice to be repeated. That life pervades and upholds all things, so that whoever accepts it by faith has all the benefit of the entire sacrifice of Christ. By Himself He "made purification of sins." Whoever rejects the life, or is unwilling to acknowledge that the life which he has is Christ's life, loses, of course, the benefit of the sacrifice. (The Glad Tidings)

While God has desired to teach men that from His own love comes the Gift which reconciles them to Himself, the archenemy of mankind has endeavored to represent God as one who delights in their destruction. Thus the sacrifices and the ordinances designed of Heaven to reveal divine love have been perverted to serve as means whereby sinners have vainly hoped to propitiate, with gifts and good works, the wrath of an offended God. (PK 685)

For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God. (1 Pet. 3:18)

I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. (Rom. 12:1)

6Wherewith shall I come before the LORD, and bow myself before the high God? shall I come before him with burnt offerings, with calves of a year old?

7Will the LORD be pleased with thousands of rams, or with ten thousands of rivers of oil? shall I give my firstborn for my transgression, the fruit of my body for the sin of my soul?

8He hath shewed thee, O man, what is good; and what doth the LORD require of thee, but to do justly, and to love mercy, and to walk humbly with thy God? (Micah 6)

Richard, Jesus was born with the sins of the world. He was made sin for us. He bore them about in His body from the cradle to the cross. True, He did not begin to pay our sin debt of death until Gethsemane, nevertheless, sin tormented Him throughout His entire life. He "suffered being tempted". (Heb 2:18)

In the wilderness of temptation, the glory of God departed and left Jesus to do battle alone with Satan. This separation and encounter with sin and Satan was similar to what Jesus went through on the cross but for very different reasons. Jesus suffered daily bearing about the sins of the world in His body but it wasn't until Gethsemane and the cross did He also endure the wrath of God against sin.

2 Corinthians
5:21 For he hath made him [to be] sin for us, who knew no sin; that we might be made the righteousness of God in him.

1 Peter
2:21 For even hereunto were ye called: because Christ also suffered for us, leaving us an example, that ye should follow his steps:
2:22 Who did no sin, neither was guile found in his mouth:
2:23 Who, when he was reviled, reviled not again; when he suffered, he threatened not; but committed [himself] to him that judgeth righteously:
2:24 Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed.

"When Jesus entered the wilderness, He was shut in by the Father's glory. Absorbed in communion with God, He was lifted above human weakness. But the glory departed, and He was left to battle with temptation. It was pressing upon Him every moment. His human nature shrank from the conflict that awaited Him. {DA 118.1}

"After the foe had departed, Jesus fell exhausted to the earth, with the pallor of death upon His face. The angels of heaven had watched the conflict, beholding their loved Commander as He passed through inexpressible suffering to make a way of escape for us. He had endured the test, greater than we shall ever be called to endure. The angels now ministered to the Son of God as He lay like one dying. He was strengthened with food, comforted with the message of His Father's love and the assurance that all heaven triumphed in His victory. {DA 131.1}

"Christ bore the penalty of sin, the stroke of divine justice, that human beings might not be left to perish. He bore in His body the sentence pronounced against sinners. This is the science of salvation, which can safely be searched into, and which it is profitable to strive to understand. {UL 196.5}