It says in the description that there are so many flows of power used to make that thing that Rand cannot even "begin to count" them. The description of the feeling of power used and the way Callandor is glowing incredibly brightly also suggests that a huge amount of power was used to make it. The only other time Rand considers a weave like this is when facing the Seanchan WITH Callandor, again implying that a sa'angreal is required.

All in all, it seems likely that Rand alone cannot do what he did here. Certainly it could probably be done in links with several others, but somekind of power boost is surely needed.

BTW. How do you know LTT did not use a sa'angreal at the sealing? Not that it necessary matters here. Placing the seals could well have been a question of skill/delicate channeling rather than strength.