The stock tyre size equates to 29", though 31" would be the maximum on stock suspension. You may squeeze 32s under there with stock suspension but it depends on what the actual tyre height is. You may want to measure them before fitting stock suspension an dthen finding they rub.
Light or heavy duty is related to the leaf pack rating which in turn is related to the total vehicle weight but seems to have become a marketing saying.
Your CJ5 is pretty light for a CJ with no winch, hardtop or big bumpers so it would have come with a light duty set of leaf packs, probably 5 leafs in number. If you fit Heavy Duty packs, say with 7 leafs, it will not lean enough.
BagusJeep lives in Bali.
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE