Good for you on giving him\her a better home. As for the sex im leaning towards female.
If you want a big snake alot goes towards rescues, 4yrs old is still young and they have calmed down and got their adult temperament... So many need homes.
After all I got a Viv and the big ol' girl for £120 and an hour's Viv scrubbing.
1.0 75% SD retic .... 6ft Hector cb17 1.1kg
0.1 coastal X ij carpet... Hielo cb15 8kg
Same, I've wanted a large carpet for so long. Weighed her today,
She is 17.6lb so 8kg:-) good size girl/boy.
We are calling her Hielo, seems to suit her.
1.0 75% SD retic .... 6ft Hector cb17 1.1kg
0.1 coastal X ij carpet... Hielo cb15 8kg