In this paper, we investigate the static tunnel allocation problem in multigraularity optical cross-connect (MG-OXC) networks. Our goal is to allocate a set of tunnels that minimize the blocking probability for the dynamic traffic that will follow the prior-known historical traffic matrix. A heuristic Capacity-Balanced Static Tunnel Allocation (CB-STA) has been proposed, which always tries to allocate a tunnel from the node with maximal predicted traffic going out to the node with maximal predicted traffic coming in. However, the tunnel length constraint is not carefully considered while selecting node pairs. Thus, this work proposes a heuristic, Weighted Tunnel Allocation (WTA), to improve CB-STA. WTA adds some additional edges with predefined hop length, termed auxiliary links, to the original topology to form an auxiliary graph. Node pair incident to an auxiliary link means that there could be tunnels allocated for it. By routing the historical traffic on the auxiliary graph, preference of tunnel allocation for each node pair incident to the auxiliary link can be estimated. Finally the tunnels will be allocated according to the preference. The simulation results show that WTA outperforms CB-STA in all switching type combinations.